Middle distillate fuel composition



United States Patent Q MIDDLE DISTILLATE FUEL COMPOSITION Maurice E.Stanley and Levi C. Parker, Port Arthur,

Tex., assignors to Texaco Inc., a corporation of Delaware This inventionrelates to a hydrocarbon fuel composition having improved non-corrosiveand stability properties. More particularly, this invention relates to ahydrocarbon fuel composition having incorporated therein a high estercontent, high viscosity oxidate which has the dual function of ananti-corrosive and a dispersant in the fuel. This application is acontinuation-in-part of copending application S.N. 636,514, filedJanuary 28, 1957, now abandoned.

Petroleum oxidates have been proposed as rust inhibitors in almost everytype of petroleum fraction. Although rust and corrosion protection areof great importance in petroleum fractions utilized as fuels, there isalso a definite need to provide protection against deposit formation.The problem of deposit formation is more prevalent in the middledistillate fuels, for example, diesel fuels, jet fuels and furnace oilswhich have been subjected to oxidizing conditions, such as long storagewhich in turn causes deterioration as evidenced by sludge and sedimentformation. Usually, when deposit-forming tendencies exist in a fuel, anadditive specifically designed to combat oxidation or a dispersingadditive, to keep the deposits from fouling the system, is incorporatedin the fuel.

In accordance with the present invention a fuel composition boilingwithin the range of middle distillate fuels has incorporated therein arust inhibiting and a depositdispersing amount of a special type ofpetrolatum oxidate characterized by a ratio of neutralization number(neut. No.) to saponification number (sap. No.) below about 0.25 and aviscosity (Saybolt Universal) at 210- F. of at least about 1,500 secondsto about 20,000 seconds and preferably in the range of about 2,500 to12,000 seconds. This special type of petrolatum oxidate is unique inimparting both anti-rust and dispersant properties to middle distillatefuels. Suitable petrolatum oxidates of this character have a maximumneut. No. of about 35, sap. No. between about 100 and 155, and containnot more than about 50 percent of unsaponifiables.

The petrolatum oxidates employed in these compositions are obtained byoxidizing petrolatum with air in the presence of a catalyst at anair'feed rate of to 35 standard cubic feet of air, per pound ofhydrocarbon, per hour, at a temperature between 270 and 400 F. and atatmospheric pressure. The preferred feed stocks employed for obtainingthe oxidates for use according to this invention are heavy petrolatumsuitably containing from about 1 to 25 percent of oil obtained fromnaphthenic, paraflinic or mixed base crude oils. Under the aboveconditions the viscosity of the oxidate increases rapidly during theoxidation and if the oxidation period is extended sufficiently, itbecomes a plastic mass at 210 F. With the type of feed stock described,the neut. No. also increases under these conditions to a maximum valueof about 35 and the sap. No. to a maximum value of about 155. Theoxidation is carried out until a product is obtained having a viscosityof at least about 1500 seconds Saybolt Universal at 210 F., andpreferably between 7 Patented June 21, 1960.

2,5 00 and 12,000 seconds, although more viscous products may beemployed if desired. A more complete explanation of the method ofpreparation and examples thereof are set forth in US. Patent No.2,705,241, issued March 29, 1955, to John K. McKinley, Gordon S. Bright,and Roy F. Nelson.

The deposit dispersing amount of the high ester con tent high viscositypetrolatum oxidates of-this invention ranges from 2 to pounds perthousand barrels of base fuel. The preferred amount, however, on thebasis of economy and performance ranges from 5 to 20 pounds per thousandbarrels of fuel.

The middle distillate fuels in which the high ester content, highviscosity petrolatum oxidates are effective dispersants and anti-rustagents include hydrocarbon fractions boiling within the range of about100 to about 750 F. or within the jet fuel to light gas oil range.Included along with straight run middle distillate fuels, are thermaland catalytically cracked hydrocarbon fuels and mixtures of crackedfuels and straight run fuels distilling within the given range. Both thecracked fuels as well as the blends of cracked and straight run fuelsmay be acid or caustic treated to improve their stability. Middledistillate fuels which have a marked tendency toward sludging anddeposit formation are primarily cracked fuels or blends which arecomposed mainly of cracked fuels. The

so-called light and intermediate cycle gas oil fractions from thermalcracking and catalytic cracking, and which are economically used infurnace oil blends and economy diesel fuels, are particularly prone toform deposits.

Included within-the scope of this invention are middle distillate fuelcompositions containing the prescribed high ester content high viscositypetrolatum oxidate, in combination with a Schiffs base reaction productof 1 mole of an aliphatic polyamine having two primary amino groups with2 moles of an aromatic aldehyde. Schifis base reaction products have thegeneral formula: I j

where A represents an aromatic nucleus and R is an aliphatic radicalhaving two nitrogen atoms attached 'directly to different carbon atomson the same open chain. Compounds of this type which generally are usedin a concentration of about 0.5 to 10 pounds per thousand barrels offuel in combination with the petrolatum oxidatedisalicylidene-1,Z-diaminopropahe.

normally act as metal deactivators as disclosed in the Downing et a1.U.S. Patent No. 2,282,513. A' preferred compound of this class, which iscommercially available, is disalicylal propylenediamine which is alsoknown as Examples of other compounds of this type are the following:di-(Z-hydroxy- 3-methoxybenzal) ethylenediamine, di-(Z-hydroxybenzal)ethylenediamine, di-(2-hydroxybenzal) decamethylenediamine,di-(Z-hydroxybenzal) triethylenetetramine, di-(Z- hydroxybenzal)hexarnethylenediamine, di-(Z-hydroxybenzal) 1,3-propylenediamine,dibenzal ethylenediamine, dibenzal hexamethylenediamine, dibenzaldiethylenetriamine, dibenzal triethylenetetramine, and disalicylalethylenediamine.

These metal deactivators by themselves do not act as fuel stabilizersbut, surprisingly, when used in combination with a high ester content,high viscosity petrolatum oxidate, they lend added stability to the fuelwhich in turn prevents color degradation of the fuel-petrolatum oxidatemixture after storage. The preferred additive amount of this compound inthe fuel is from about 1 to 5 pounds per thousand barrels.

A number of tests were used in the development of the stable fuelcompositions of this invention. The basic deposit determination testinvolved vigorously shaking the fuel composition'which had been storedfor a period of time to obtain a representative sample. A 150 ml. samplewas removed and filtered under vacuum through a No. 1 Whatman filterpaper disc. The filterdiscs were retained for visual observation andcomparison of the discoloration due to retained sediment.

The following table showing the results of the above test is set forthto demonstrate the stability of a fuel composition of this invention ascompared to the. base fuel and several other related type fuelcompositions.

The base fuel comprised a blend of 30 vol. percent of a heavy kerosinedistillate having an API gravity below 42 derived from an asphalt basecrude and 70 vol. percent of a fluid cracked light cycle gas oil. Testresults on the base fuel were as follows:

Gravity, API Flash, P.M., F. 172 Viscosity, S.U. 100 F. 34.0 Color, ASTM2.5 Pour, F. 7 -25 Carbon residue (10% btms.) 0.02 Corn, cu. strip at122 F Neg. 1 Sulfur, wt. percent 0.22 Ash, wt. percent None Cetane No.41.4 Aromatics, vol. percent 24 Olefins, wt. percent Distillation, F.:

I.B.P. 386

In this test the comparative terms of very slight, slight, medium,heavy, and very heavy, to designate the amount of deposits or sedimenton each filter disc, were used.

In the following table and in subsequent tables the amount of additivegiven as present in the base fuel and the description thereof is basedon the active ingredients. Oxidates A and B, which were derived frompetrolatum and paraffin waxes, respectively, are completely soluble inmiddle distillatefuels. However, in order to facilitate handling, eachof these oxidates was cut back with a portion of thebase fuel prior toincorporation in the fuel tested. On the other hand, the acid-typeparaffin wax oxidate from which oxidate C was derived was only about 75to 80 percent soluble in a middle distillate fuel. Accordingly, thissoluble portion of this. acid-type oxidate material was termed oxidate Cand the cut-back oxidate was added in the desired amount to the fueltested. The additive. amounts shown in the tables in each case wereconsidered to be equivalent thereby allowing comparison of theeffectiveness of these oxidates.

TABLE I Basic deposit determination test The oxidate A" in the abovetable was a high ester content, high viscosity microcrystallinepetrolatum oxidate having a neut. No. of 25, a sap. No. of 145, andneut. No. to sap. No. ratio of 0.17 and an unsaponifiable contentlessthan 50 percent. Oxidate B consisted of an ester typemacrocrystalline .wax oxidate having a neut. Nani 84, 21 san. No. of 230a neut. No. tqfi pratio of 0.37 and an unsaponifiable content less than40 percent. Oxidate C consisted of the fuel soluble portion (75 topercent solubility) of an acid-type macrocrystalline wax oxidate havingan average neut. No. of 232, an average sap. No. of 380, an averageneut. No. to sap. No. ratio of 0.61, and an unsaponifiable content lessthan 16 percent.

The results in the above table demonstrate the particularity of theinvention with respect to the specific oxidate necessarily employed inobtaining a stable fuel composition.

The petrolatum oxidate of the invention has a much lower neut. No. toSap. No. ratio than those wax oxidates showing no dispersing properties.Oxidate A also differs from oxidates B and C in that it is amicrocrystalline wax oxidate rather than a macrocrystalline.

Another test used in the determination of the dispersant qualities ofthe fuel compositions of this invention was the accelerated filter paperdepositv test which consisted of placing a 170 ml. sample of the fuel ina Pyrex glass cell and heating the fuel sample for 2 hours at 275 F. bymeans of a bath in which the cell was immersed. The glass cell wasprovided with air inlet means at the bottom thereof through which aircould be forced or bubbled through the fuel sample therein. Air wasbubbled through 20 percent caustic and Water andv then through themiddle distillate fuel sample in the cell at the rate of 0.3 liter perhour. At the end of 2 hours at 275 F., the fuel was removed and cooledto room temperature within approximately 1 hour after removal. sample ofthe fuel was then filtered under vacuum through a No. 1 Whatman filterpaper disc. The filter discs were retained for visual observation andcomparison of the discoloration due to retained sediment.

In Table II there is shown the improvement obtained in the acceleratedfilter deposit test by adding a high ester content, high viscositypetrolatum oxidate to the base fuel described in Table I. For purposesof comparison, there are also shown the results obtained in this test byadding two different parafiin wax oxidates to the same base fuel. Thesamples were not stored prior to testing.

TABLE II Accelerated filter deposit test Fuel Sample Deposit FormationBase f l heavy. Bass fuel 12 lbs. of Oxidate A 1,000 bhls. of fuelslight. Base fuel 12 lbs. of Oxidate B/l,000 bbls. of fueL. heavy. Basefuel-+ 12 lbs. of Oxldate 011,000 bbls. of fuel heavy.

The accelerated deposits test was designed to simulate a situationwherein the fuel composition had been exposed to oxidizing conditionsfor a lengthy period. It can be seen from the above table that theoxidate of this invention (oxidate A) is extremely effective in reducingdeposit formation. On the other hand, the more acidic macrocrystallinewax oxidates (B and C) are ineffective with respect to dispersantqualities.

In order to ascertain the ability of a high estercontent, high viscositypetrolatum oxidateto stabilize the depositforming tendencies of the fuelafter actual storage for comparatively long periods of time, severalfuel compositions of interest including the fuel composition of theinvention were held in vented dark storage at room temperature forsixand twelve-month periods. These samplcs were then evaluated basis (1)visual observation of storage samples, (2) color, carbon residue, andinsoluble residue of storage samples, and (3) basic depositdetermination tests.

The base fuel used during this phase of experimentation was thatdescribed in connection with the experiments shown in Table I.

The results from the visual observations o the deposits formed duringthe sixmonths storage at room temperature indicated that the high estercontent, high viscosity petrolatum oxidate of the invention in a dosageof 12 lbs. per thousand barrels of fuel significantly reduced depositformation. It appears to be rather generally agreed throughout theindustry that observation of room temperature samples for deposits afterlong-term storage is the best single criterion for establishing thestability of middle distillate fuels.

The color of the fuel composition of the invention had satisfactorystability. The original N.P.A. color was L2 /2. After six months storagethe sample had darkened to only L3.0, and after twelve months storagethe sample had darkened to L3 /z.

The amount of carbon residue present was also very satisfactory.Analysis of percent bottoms after six months storage showed only 0.08wt. percent. No carbon residue determination was made after twelvemonths storage.

Insoluble residue, basis the Du Pont F 8-52 residue test was also veryslight. The results of this test 'on the fuel composition of theinvention after six months storage showed only 0.7 mg. per 100 ml. and1.0 mg. per 100 ml. after twelve months.

The following table shows the results of the basic deposit determinationtest on the fuel compositions stored for six and twelve months.

TABLE III Again, after sixand twelve-month storage periods the fuelcomposition of the invention with oxidate A showed a marked ability tostabilize deposit formation in the fuel. The more acidic paraflin waxoxidates (B and C), however, showed no ability as fuel stabilizers.

The additive of the invention was also tested in a base fuel having asomewhat higher percentage of a cracked component therein. The base fuelin this case consisted of 20 vol. percent of an acid-treated heavykerosine distillate having a API gravity below '42 derived from asphaltbase crude and 80 vol. percent of a fluid cracked light cycle gas oil.Test results on this fuel blend are as follows:

Gravity, API 36.7 Flash, P.M. F. 154 Viscosity, S.U. 100 F. 33.2 Color,ASTM L2 /2 Pour, F. ---20 Car. res. (10% btms.) 0.07 Corr. cu. strip at122 F. Neg. 1 Sulfur, wt. percent 0.31 Ash, wt. percent -1 None CetaneNo. 46.4 Aromatics, vol. percent 2.3 Olefins, wt. percent 3Distillation, -F.:

I.B.P. 3'72 50% 474 E.P. 602

Samples of this fuel containing a high ester content,

6 vented containers kept in the dark for various periods of time and atvarious temperatures as follows:

(A) 1 month at 130 F. (B) 3 months at 110 F. (C) 3 months at roomtemperature Visual observations of the deposits formed during storageare presented in the following table:

TABLE IV Observation of storage deposits Three months at- One month at130 F.

110 F. room temp.

Base fuel Base fuel 12 lbs of Oxidate A/1,000 bbls.

medium..

s1ight-medium.. very slightslight. very slight very slight.

The samples stored at 110 F. were subjected to testing in the oronitefilter test which consisted of vigorously shaking a 150 ml. sample ofthe fuel to be tested with 25 ml. of distilled water for 15 to 20seconds. The resulting mixture was filtered under vacuum through a No. 1Whatman filter paper disc. The filter discs were retained for visualobservation and comparison of the discoloration due to retainedsediment. The samples stored at 130 F., as well as those stored at 110F., were tested using the previously described basic .depositsdetermination test which difilered from the oronite filter test in thatthe sample was notshaken with water prior to filtering. The acceleratedfilter paper deposit test and oronite filter test were also used to testthe fuel composition before storing.

The results of these tests which show the superiority of a fuelcontaining 12 lbs. of the high ester content, high viscosity petrolatumoXid'ate (oxidate A) per thousand barrels, with respect to stability,are given in the following tables:

TABLE V v Oronite filter test Storage Sample 7 Deposits Time, Temp., mo.F.

Base fuel -f Before storage slight. Base fuel Oxidate A-.." Beforestorage very slight. Base fuel mediumheavy. Base fuel Oxidate A 3 110slight.

TABLE VI Accelerated filter paper deposit test Storage Sample DepositsTime Temp.

Base fuel Before storage .heavy. Base fuel Oxidate A Before storageslight.

TABLE VII Basic deposit determination test Storage 7 Sample DepositsTime, Temp., mo. F.

1 heav I 1 130 very slight. fu .4; 3 110 heavy. Base fuel Oxidate A '3'110 slight.

The. above tables again amply demonstrate the dispersant quality of, theoxidate additives. of. this invention under various test and storageconditions.

Another test procedure used to demonstrate the effectiveness of the fuelcomposition of theinvention was the Enjay accelerated filter pluggingtest which has recently been widely publicized as an excellentmethod.for determining fuel stability. The Enjay filter plugging test consistsof aging 4.5 gal. of the fuel composition to be evaluated in a steamchest for 16 hours with the fuel temperature raised from 77 F. to 235 F.at a specified rate. The fuel is then cooled to about 72 F. within 4hours. and the filter plugging characteristics determined by' filtering12 liters at a constant rate through a woven felt pad which waspreviously rinsed with n-heptane, dried and weighed. As depositsaccumulate on the pad, the pressure drop across the pad increases. Afterthe 12 liters of sample fuel have been filtered, a record is made of thefinal pressure drop, the weight of sediment of the pad, and theappearance of the pad. These values are expressed as demerit ratings andaveraged to obtain an over-all accelerated filter plugging demeritrating. The demerit rating range runs from zero to ten where zero meansa perfect pad with no discoloration and no appreciable pressure drop,and where ten means a very badly discolored pad with high weightincrease and extreme pressure drop.

The following table shows the results. of the Enjay accelerated filterplugging test on the fuel compositions of, the invention and similarfuel compositions for comparison. The base fuel was that described asused in Tables IV, V, VI, and VII.

following table shows the, results of the quickie; corrosion test on thefuel composition of the invention in comparison with the. base fuel. Thebase fuel used in this test was that described in connection with thetest results shown in Table I.

The above table shows that the oxidate of the invention provides.excellent rust protection in middle distillate fuels as compared to aknown oxidate rust inhibitor (oxidate B).

As previously stated, included within the scope. of this invention aremiddle distillate fuel compositions containing the. specific high estercontent, high viscosity petrolatum oxidate of this invention incombination with an amine metal deactivating compound such as thepreferred disalicylal propylenediamine. The following table sets forththe results of deposits tests of fuels containing the additivecombination of the invention. The test used was the basic depositdetermination test previously described. The test samples were stored indark vented TABLE VIII Demerlt Ratings FuelSample Appearance WeightPressure Over-all Average Base iuel, 1st run 9 6 5 6. 7 Base fuel, 2ndrun 9;; 7 3 6- 6 5 Base Fue1+12 lbs. of Oxldate A per 1,000 bbl s, of

fuel, 1st run 1 0 0 0- 3 Base Fuel+12 lbs. of Oxidate A per 1,000 bbls.of fuel,

2nd run 7 V 1 1 Q 0. 7. o 5 Base Fuel+12 lbs. of Oxidate B per 1,000bbls. of fuel,

1st run- 6 5 1 4. 0 Base Fne1+12 lbs. of Oxidate B per 1,000 bbls. offuel,

2nd run v 5 2 3 Base Fuel-H2 lbs. of Oxidate B per 1,000 bbls. of fuel,

3rd run 4 6 2 4. 0 4 1 The results in this test give added proof of theexcellent fuel stability shown to be produced by the high ester content,high viscosity petrolatum oxidate of the invention in the previouslydescribed stability tests;

The high ester content high viscosity petrolatum oxidate of theinvention, similar to wax oxidates, is an excellent anti-corrosive inlubricating oil which is disclosed in US. Patent No. 2,705 ,241. Itsanti-corrosive property in'middle distillate fuels was demonstrated bythe results of a slightly modified quickie corrosion test. The modifiedquickie corrosion test. consisted. of contacting a polished steel stripwith 115 ml. of the test fuel composition in a tall 4 oz. bottle. Thestrip and test fuelj were allowed to stand for 15 minutes before 20ml..of the test. fuel were removed and replaced by 20 ml. of distilledwater. The bottle was then shaken for 15 seconds in a horizontalposition, given a short swirl to sweep the large water drops from thestrip and placed upright. Readings of the percentage of rust on thefront and back of the strips were made after 3 hours at 120 F., andafter anadditional 24 hours at room temperature. The corrosion readings,of the strip of steel in the fuel phase were expressed as percent of thesurface of'the strip covered by rust. The

containers for 3 months at F. They werevi'gorous- 1y shaken prior totesting in orderto obtain a representative test sample. The base fuelused in these tests was that described in connection with the testing ofthe fuel compositions, the results of which are shown in Tables IV, V,VI, and VII.

The above table shows the ability of a combination of petrolatum oxidateand disalicylal propylenediamine to stabilize the fuel. The'combinationis somewhat more .efiective, thanthe petrolatum oxidate alone alt oughthere 9 is apparently no appreciable stability produced by thedisalicylal propylenediamine alone. Further, the combination produces amore color stable fuel than the fuel composition containing only theoxidate of the invention.

Freezing pt., F. Below ---76 Smoke pt., mm. 24 Sulfur, percent 0.023Mercaptan sulfur, wt. percent 0.002

The following table shows the results of tests which Aromatics, vol.percent 11.0 also demonstrate the superior stabilizing effect on amiddle Olefins, wt. percent 1.0 253 513 5 52 ggy zgggfigg g fif gii gg zg z The thermal stability additive of the invention was cut back tofacilitate handling by blending by wt. of the gh g g g g g ti i g? 2 iggi i gi gg high ester content, highviscosity petrolatum oxidate with dd f by wt. of naphthemc petroleum distillate showing the pro uct pro ucee o owing resu ts. following test results:

o 2 2 E g: Gravity, API 0 34.4 viscosm; gab F 35 0 V1se0S1ty,SSU t 100 8Color 15 Fla h, C.T., F. 165 Pour Sulfur, percent 0.082 Car. res. (10%btms.) 0.06 fi i izig stnl; 22: g Aromatics, vol. percent 19 u w Pe c 20Olefins, wt. percent 2 Ash, wt. percent 0.003 0 Cetane No 50 6Distillation, F..

I.B.P. 384 Aromatics, vol. percent 19 10 418 Olefins, wt. percent 4 50462 Distillation, F.:

I.B.P. 404 BR 538 0 The amount of the additive of the inventlon, forconvenience termed oxidate A, was given for the active in- .0 {on jectedto vented dark storage for 3 months at room temg zg g g g g i i E 83 5 ifi 332g;

fz gs g'g g z gg i gggg gzfi z fgi gigpii prior ture of 400 F. and afuel flow of 6 lbs./hr. forS hours.

TABLE XI TABLE XII S m 19 De as"; CFR fuel coker test a p Forn iationPressurebuild- Base mp] medium- Run Fuel Sample up iagrgss fllgser, Basefuel-H2 lbs/1,000 bbls. of OxidateA slight. 40 agi; Base inel+12 lbs. ofOxidate A per 1,000 bbls. and 2 lbs./ very slight.

1,000 bbls. of disalleylal propylenedlamlne.

; Base fuel fi Again, it is obvious from the above table that the comaan 6. 70 a i of the invention is an exceptionally good fuel 1211,541,000 of 81% stablllzel. Oxidate A.

To demonstrate the exceptional ability of the high ester 2: 8:58content, high viscosity petrolatum oxidate of the inven- R dn 0.05 tionto improve the thermal stability of jet fuels, the CFR fuel coker testwas used. This test comprises utilizing an apparatus Specificallydesigned for measuring high Current commerical specifications designate12 niches temperature stability of jet fuels. It mainly consists of a of.mercury as the allowable Pressure bufld'up fuel storage zone, pumpmeans to carry the fuel through Oxldate A exerts an unexpfactedInfluence on the l a flow meter, a preheater, filtering means, a needlevalve to lower the pllessure across the filter m this and to the drain.The test is run by adjustment of a 6:; an ifgz' g t d th fu 1 pressureregulator in the system, fuel flow, and the temer a f {nay ig 6 1peratures of the preheater and filter assembly. The duraposmon o imvelmon W1 out p i tion of the test is governed by a limiting pressurediftherpto Addliwes l' suppress deposlt i i p ferential of 25 inches ofmercury across the filter or an conluncnon with the hlgh ester contenthigh vlscoslty arbitrary time limit of 300 minutes petrolatum oxidatemay at times be extremely useful.

The jet fuel which is presently being used in the greatest Fexfunpleha.copolymer 2 2 f i P amounts by'the military and certaincommercial aircraft mg ong C 31-11 compoun aving equl S ant reactwe isthe IP-4 type This fuel must meet the requirements groups A pamcuhircompo-11nd 1s a copolymer of lmiryl MIL F 5624 methacrylate anddiethylaminoethyl methacrylate WhlCh,

The base fuel u'sed in this test was a fuel Showing when mcorporated ina fuel, reacts with nitrogen, sulfur the followin test results whichmeet the above military 05 and oxygenated compounds to prevent Sludgmg'The r long chain structure enables the copolymer to stay in clmremensolution in the fuel. Gravity, API 50.1 Still other additives, forexample, metal petroleum sul- Distillation, F.: fonates, either basic,neutral, or combinations thereof,

I.B.P. 140 are sometimes advantageously incorporated in the fuel 20% 230compositions of this invention as additional stabilizers 50% 303 ordispersants.

90% 447 Obviously, many modifications and variations of the in- ER 500vention, as hereinbefore set forth, may be made without Aniline pt., F.127.9 departing from the spirit and scope thereof, and, therefore, onlysuchlimitations should be imposed cated in the appended claims. i 1

We claim: Y

1. A hydrocarbon fuel boiling within the range of about 100 to 750 F.containing, from 2 to 30 pounds per thousand barrels of apetrolatumoxidate characterized by a ratio of neut. No. to sap. No. below about0.25 and an SUS viscosity at 210 F. of at least about 1,500 to 20,000,said amount being suificient to disperse deposits in the fuel.

2. A hydrocarbon fuel composition as described in claim 1 wherein theSUS viscosity at 210 F. of the oxidate ranges from about 2,500 to12,000.

3. A hydrocarbon fuel. as described in claim 2 wherein the amountrangesfrom .about 5 to. 20 poundsv per thousandbarrels of fuel. 7

'4. A. hydrocarbon fuel boiling withinthe range of from 100 to 750 F.containing from 5 to 20 pounds per thousand barrels of. a petrolaturnoxidate having a maximum neut. No. of 35, sap. No. range of from 100, to155, a neut. No. to sap. No. ratio of below about 0.25 and an SUSviscosity at 210? F. of 2,500 to.12,000.

5. A hydrocarbon fuelboiling Within the range of from 100 to 750F..containing from 2 to 30 pounds per thousand barrels of. a petrolatumoxidate characterized by a as are indi-v 1'2 neut; No. to sap. No. ratioof below 0.25 and an SUS viscosity at 210 F., of from 1,500 to 20,000,andfrom 0.5 to 10 pounds per thousand barrels of a Schifis base reactionproduct of 1' mole of an aliphatic polyamine at least two primary aminogroups attached to dilferent carbon atoms of the same open chain with atleast 2 moles V of an aromatic aldehyde.

6. A hydrocarbon fuel as described in claim 5 wherein the Schifis basereactionproduct is disalicylal propylenediamine in an amount between 1and 5 pounds per thousand barrels of fuel.

References Cited in the file of this patent UNITED STATES PATENTS Patentshould read as correc UNITED STATES PATENT OFFICE CERTIFICATE OF'QORRECTEON Patent No; 234M876 Maurice E.a Stanley et al.0

s in the-printed specification tion and that the said Letters June .211960 It is hereby certified that error appear of the above numberedpatent requiring correc ted below. Column l2. line l after "polyamine"insert having 5 Signed and sealed this 8th day of November 1960a (SEAL)Attest:

ROBERT C. WATSON KARL H. AXLINE Attesting Oflice r Commissioner ofPatents

1. A HYDROCARBON FUEL BOILING WITHIN THE RANGE OF ABOUT 100 TO 750*F.CONTAINING FROM 2 TO 30 POUNDS PER THOUSAND BARRELS OF A PETROLATUMOXIDATE CHARACTERIZED BY A RATIO OF NEUT. NO. TO SAP. NO. BELOW ABOUT0.25 AND AN SUS VISCOSITY AT 210*F. OF AT LEAST ABOUT 1,500 TO 20,000,SAID AMOUNT BEING SUFFICIENT TO DISPERSE DEPOSITS IN THE FUEL.